1. Field of the Invention
The present invention relates to a seat rail locking system for a vehicle, which is modified in its construction to control forward and rearward movement of an upper rail relative to a lower rail, with the upper and lower rails constituting a seat rail assembly, and to thereby ensure comfort of an occupant.
2. Description of the Related Art
Vehicle seats function to support occupants in a sitting position. Generally, vehicle seats are divided into a separation type seat which is used as a driver""s seat and a front passenger seat to allow only one person to sit thereon and a bench type seat which is used as a rear passenger seat to allow several persons to sit thereon at the same time.
In the case of the separation type seat which is used as the driver""s seat and the front passenger seat to allow only one person to sit thereon, a seat rail assembly is provided such that the seat is placed on the seat rail assembly. The seat rail assembly allows the seat to be slidingly moved forward and rearward depending upon a body figure of an occupant to thereby ensure riding comfort.
The seat rail assembly comprises an upper rail which is fastened to a floor panel of a vehicle body and a lower rail to which the seat is secured. In the seat rail assembly, the upper rail having secured thereto the seat can slide on the lower rail to be moved forward and rearward. In order to control movement of the upper rail on the lower rail, a seat rail locking system is provided.
Referring to FIGS. 11 and 12, a conventional seat rail assembly 1 comprises a lower rail 3 which is fastened to a floor panel of a vehicle body by the medium of fastening brackets, and an upper rail 4 which is operatively coupled with the lower rail 3 and to which a seat is secured.
Both widthwise ends of the lower and upper rails 3 and 4 are formed with outward and inward flanges 5 and 6, respectively. Balls 7 or a pair of ball seats or rollers having balls, serving as means for allowing the upper rail 4 to easily slide on the lower rail 3, are intervened between the outward and inward flanges 5 and 6.
Of course, the seat rail assembly 1 is provided with a seat rail locking system 10 which is configured to permit forward and rearward movement of the seat and maintain the seat in a desired position. The seat rail locking system 10 comprises a plurality of locking holes 11 which are defined in the lower rail 3 and a locker 12 which is provided to the upper rail 4. The locker 12 is fastened to a rod member 14. Due to the fact that the rod member 14 is rotatably supported by a locker guide plate 13 which is fastened to the upper rail 4 and a coil type spring (not shown) is wound around the rod member 14 to bias it in one rotating direction, the locker 12 is hingedly supported by the locker guide plate 13 by the medium of the rod member 14.
The conventional seat rail locking system 10 suffers from defects in that, since the locking system 10 is configured to project out of the seat rail assembly 1, an outer appearance of the seat rail assembly 1 is deteriorated. Also, as component elements of the locking system 10 have a substantial thickness and length so as to satisfy strength and durability required for the seat rail locking system 10, a weight of the seat rail assembly 1 cannot but be increased.
Specifically, after the seat rail assembly 1 is mounted to the vehicle body, in order to ensure that the seat rail assembly 1 is prevented from being damaged, deformed or unintentionally disassembled due to shock transferred to a vehicle while traveling on a road, since the lower and upper rails 3 and 4 must have a substantial thickness to reinforce strength of the seat rail assembly 1, a current trend of a vehicle toward light weight and reduced fuel consumption cannot be properly met.
Further, the seat rail locking system 10 is configured in a manner such that the plurality of locking holes 11 are defined in a bent portion of the lower rail 3 constituting the seat rail assembly 1 and the locker 12 is located at a side of the locking holes 11 to be rotatingly engaged into one of the locking holes 11 to thereby maintain the seat in a locked position. For this reason, in the process of operating the seat rail locking system 10 after mounting it to the seat rail assembly 1, a load is concentratedly applied to the seat rail assembly 1 at a region where the seat rail locking system 10 is mounted to the seat rail assembly 1. As a consequence, material fatigue is increased, and upon a head-on collision or a rear-end collision, the upper rail 4 is likely to be unintentionally separated from the lower rail 3 due to the presence of the seat rail locking system 10.
Moreover, since the lower rail 3 is bent in a state wherein the plurality of locking holes 11 are defined and therefore the lower rail 3 must be designed in consideration of after-bending deformation, problems are caused in that careful attention must be paid to tolerance over the entire seat rail locking system 10, and thereby a manufacturing cost of the seat rail locking system 10 is increased.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a seat rail locking system for controlling movement of a vehicle seat, which is modified in its construction to be installed inside a seat rail assembly composed of upper and lower rails and not to be exposed to the outside, thereby improving an outer appearance of the seat rail assembly, and which has a simple configuration while ensuring operational reliability and improving durability, merchantability and productivity.
According to the present invention, there is provided a seat rail locking system for a vehicle, adapted for being installed in a seat rail assembly to permit forward and rearward movement of a seat and maintain the seat in a desired position, the seat rail assembly including a lower rail which is fastened at both ends thereof to a floor panel of a vehicle body by the medium of fastening brackets, an upper rail which is coupled with the lower rail and to which the seat is secured, both widthwise ends of the lower and upper rails being respectively formed with outward and inward flanges, and a pair of ball seats which have balls for allowing the upper rail to easily slide on the lower rail and are intervened between the outward and inward flanges, the seat rail locking system comprising: a locker guide fastened to the upper rail and defined at a bottom wall thereof with a guide hole; a locker received in a space defined between the upper rail and the locker guide and having an upper end which is connected to an operating lever and a lower end which is formed with locking projections to be moved upward and downward through the guide hole of the locker guide; a plurality of locking holes defined at a center portion of the lower rail to be spaced apart one from another by the same distance along a lengthwise direction of the lower rail, in a manner such that the locking projections can be engaged into selected ones of the locking holes; and a spring for biasing the locker in a direction where the locking projections of the locker are engaged into selected ones of the locking holes defined in the lower rail.